Capnometry - carbon dioxide monitoring - is widely used in both hospital and pre-hospital settings. Two types of infrared monitors, mainstream and side stream, are available. Both have multiple drawbacks, including addition of a dead space, slow system response, and erroneous readings caused by the presence of nitrous oxide and oxygen, as well as varying barometric pressure. Physical Optics Corporation (POC) proposes to develop a new Miniature Capnometer (MIC) to overcome the major shortcomings of the existing carbon dioxide monitors. MIC will be a miniature (2 mm in diameter), robust, and sensitive carbon dioxide monitor that fits easily into the endotracheal tube or into a sampling line of non-intubated patients. The device will be immune to interference from other gases exhaled by the patient, and to atmospheric pressure. POC's proposed MIC will have significantly high CC>2 sensitivity, resolution, and accuracy of monitoring. In addition, MIC will have one order of magnitude more selectivity and four to five times better response time than the state of the art devices. Phase I will culminate in a full proof-of-concept demonstration with an anesthesia system and an anesthesia mannequin.